Form described by Langton, 1991
Diagnosis
Exuviae 4.3-4.9mm long (n=4).
Cephalothorax: Cephalic tubercles short conical, 25µm high. Frontal setae 175µm long (n=1). Antennal sheath base with a weak, broad swelling. Thoracic horn 370, 385µm long; ThR 9.3, 12.8 (n=2). Thoracic horn seta 130µm long (n=2), 0.35x horn length (148k.jpg). Posterior thoracic mound moderately swollen. Pearl row absent.
Abdomen: Length hook row II 0.46, 0.49x width tergite; hooks 85, 88 (n=2). Tergite II without anterior point patches; armament may be reduced, but very faint. Tergite III with shagreen only, in which there may be a few scattered spinules (148l.jpg). Tergites IV and V with a pair of transverse, slightly oblique point patches. Lateral longitudinal bands of spines or spinules absent on tergites IV and V, though there may be a broad field of small points spreading posteriorly from the anterior point patches. Tergites VII and VIII with very restricted armament or smooth. Pedes spurii B II well-developed. Comb of segment VIII 25, 35µm wide (n=2); with 3, 4 marginal teeth (n=4). Lateral taeniae of segments IV-VIII: 3,3,4,4,5.
Anal segment: Anal lobe ratio 1.1-1.3 (n=3). Fringe of anal lobe complete, with 42-55 taeniae (n=4).
Form keys out at Page 516: Tanytarsini 157 Micropsectra of the Text Key.
Distribution
Great Britain.
(For more information see module IdentifyIt – file: Chironominae).
Ecological notes
Lakes; northern England and Scotland.